Re: [PATCH v7 10/14] arm64/numa: define numa_distance as array to simplify code

Leizhen (ThunderTown)
2016-08-27T10:31:29Z

On 2016/8/26 23:29, Will Deacon wrote:
> On Wed, Aug 24, 2016 at 03:44:49PM +0800, Zhen Lei wrote:
>> 1. MAX_NUMNODES is base on CONFIG_NODES_SHIFT, the default value of the
>> latter is very small now.
>> 2. Suppose the default value of MAX_NUMNODES is enlarged to 64, so the
>> size of numa_distance is 4K, it's still acceptable if run the Image
>> on other processors.
>> 3. It will make function __node_distance quicker than before.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>> arch/arm64/include/asm/numa.h | 1 -
>> arch/arm64/mm/numa.c | 74 +++----------------------------------------
>> 2 files changed, 5 insertions(+), 70 deletions(-)
>
> I fail to see the advantages of this patch. Do you have some compelling
> performance figures or something?

We can only put numa_distance_cnt on one node, so for the cpus of other nodes to access it should
spend more time. I have not tested how many can be improved yet.

I will try to get some data next week.

>
> Will
>
> .
>